24 November 1990

Comments about Colorado Jumbo tape backup, hardware and techniques:
******************************************************************

I recently came across a BBS file intended to simplify multi-
partition backups using the Colorado Jumbo tape backup system (qic-
40 format). I've misplaced it, but I'd noted it addressed a need, 
but one which I had already solved in a manner I personally 
preferred. 

I'll detail my method here and add a few comments I learned the 
hard way and by calling Colorado. Perhaps by now some of these will 
have been incorporated into newer documentation (I certainly 
suggested the firm do so); but then again, maybe not. 

I run a fairly loaded 386-33--386max, 8 megs ram, 2 physical hard 
drives partitioned as cdefgh and totalling 150 mBytes. A few TSRs 
as well as 1 meg cache, 3/4 meg spooler. After talking with 
Colorado, we determined I probably had some problems with TSRs so 
rather than search for the culprit, for backups I just boot from a 
fairly vanilla floppy. One problem solved. 

The tape insertion action does not have a quality feel, but 
everything works OK. On startup, the drive occasionally makes a 
horrendous clacking sound, but the noise is intermittent. Turns out 
this is the electric-screw drive which positions the head. When the 
black keyhole shaped part on the shaft (visible from the top) 
reaches its upper travel limit, it rachets in a very audible 
manner. Since it doesn't do this everytime, a user might suspect a 
problem developing. Not so. It does it depending on the head 
position when the drive was last used, so at start up you may or 
may not hear the clacking. Pity this wasn't included in the doc. 

It's also too bad there is just the single activity light. This 
makes it hard to tell when the leisurely initial tape tensioning 
process is finished, especially in a noisy environment. A couple of 
extra indicator lights would be a nice addition to the next 
hardware revision. LEDs are cheap.

Back-up batch files

I use batch files to back up cde on one tape, fgh on another. My 
4-line files look like this (back-ce.bat shown, run from the \tape 
directory): 

                tape erase
                tape backup e:\*.* >backe.log
                tape backup d:\*.* >backd.log
                tape backup c:\*.* >backc.log

This will erase the tape, then sequentially back up the three 
partitions and write separate log files, all without my further 
attention. Why separate logs? So when the back up is done I can use 
a viewing utility (list or similar) to check each, popping to the 
screen at the end to verify I had no errors. (My sequence of e-d-c 
rather than c-d-e is simply a whim.) 

If I had left the logs as a single file, I'd have to hunt for the end 
comments for the first two partitions to ensure I'd had zero 
errors. Should you want everything in a single log, use double 
redirection on the last two lines (>>) and use the same filename 
throughout. The second and subsequent partition log data will then 
be appended to the first partition's file. 

I use rotating backups, meaning I always have two full backups on 
tape; 4 tapes total. Before making the next backup I rename (on 
\tape dir) backc.log to backc2.log and so forth to avoid 
overwriting my log files until I'm through with them. 

The companion bat file, which I call back-fg.bat, is identical with 
this one except for the obvious replacement of two letters in each 
of the last three lines. 

The command "tape crt," intended to ensure that your drive 
(especially if you are using the external kit as I am), is not 
affected by monitor radiation. My monitor (NEC 4D) required I move 
the external tape drive another foot away (2 feet total) to get a 
clean reading. Colorado phone support says don't just get the OK 
and terminate--let the test continue for 10 or 15 minutes. If after 
that time you've had no errors, you can assume monitor interference 
is effectively nil. 

This stuff is hardly rocket science, but was not obvious to me from 
the documentation I was supplied. Without spending some long-
distance money I'd have never known the answers to some of this. 
There's probably more to be discovered, but just this much allows 
me to do no-pain multiple partition tape backups. Overall, the 
Jumbo hardware is working OK, and is certainly cost effective. By 
the way, listening carefully, I've determined that Colorado prefers 
3M tape to DEI (of course I had already bought DEI, but it seems 
to be OK so far). 


Dex Hart
Miami

